🔌 Cal Spas Circuit Board — CS5900R1(x) | ELE09100219 — VS300 Series Spa Control

Genuine Cal Spas VS300 replacement board powered by Balboa Water Group M7® technology.

⚠️ IMPORTANT — PLEASE READ BEFORE ORDERING

• Identify by chip number and Balboa board number. Look for chip label CS5900R1(x) — where x is any letter (revisions A through F are all covered by this board. The Balboa 5-digit board number 55237 will also appear on the white sticker. Confirm both before ordering.
• Note on part numbers 55236 and 55237. Both numbers are associated with the Cal Spas CS5900 / VS300 system — but they refer to different things. 55236 is the Cal Spas spa pack (complete control box) part number, which is now obsolete and discontinued. 55237 is the circuit board (PCB) part number — the individual board sold here. Do not confuse the two.
• Non-returnable. Cal Spas circuit boards cannot be resold as new to another owner. Confirm compatibility before ordering.
• Do not order by spa model name alone. Identify by chip number (CS5900R1(x)) and Balboa board number (55237).
• Contact Parts4Tubs before ordering if you have any questions about compatibility or your specific Cal Spas system.

📋 Product Overview

The Cal Spas circuit board CS5900R1(x) (Cal Spas OEM part number ELE09100219, Balboa circuit board part number 55237) is a genuine Balboa Water Group replacement PCB for Cal Spas VS300 series spa systems. This board uses Balboa’s M7® temperature and flow sensing technology — an integrated dual-sensor design that provides precision temperature measurement and hi-limit protection.

The board connects to Cal Spas topside panels via a phone-style cable (8-wire RJ-style connector), the standard connector format for Cal Spas VS300 era systems.

The complete CS5900 control box assembly (Balboa system PN 55236) has been discontinued by Cal Spas. However, the circuit board itself (55237 / ELE09100219) remains available as a replacement part. Parts4Tubs has 7 in stock.

✨ Key Features

✅ Genuine Cal Spas OEM circuit board — manufactured by Balboa Water Group
✅ Chip CS5900R1(x) — all revisions from R1A through R1F are covered by this OEM part number
✅ Balboa circuit board PN: 55237
✅ M7® temperature and flow sensing technology — integrated dual-sensor design
✅ Phone Style Cable (8-wire RJ-type) topside connector — standard Cal Spas format
✅ VS300 system platform — direct Cal Spas factory replacement
✅ 7 in stock — ready to ship
✅ 30-day limited warranty (Cal Spas policy)

🔩 Technical Specifications

Specification	Value
Cal Spas OEM Part Number	ELE09100219
Alternate Cal Spas Format	CALELE09100219
Balboa Circuit Board PN	55237
Note on 55236	55236 is the Cal Spas spa pack (complete control box) PN — now obsolete; 55237 is this circuit board
Chip Number	CS5900R1(x) — x = any letter (R1A through R1F)
System Series	VS300
Manufacturer	Balboa Water Group (for Cal Spas)
Technology	M7® integrated dual-sensor (temperature and flow)
Topside Connector	Phone Style Cable (8-wire RJ-type)
Input Voltage	Please confirm from your spa’s system label or contact Parts4Tubs
Heater Output	Please confirm from your spa’s system label or contact Parts4Tubs
Pump Configuration	Please confirm from your spa’s system label or contact Parts4Tubs
Compatible Sensor	Balboa M7 Sensor Assembly — 53605
Warranty	30-day limited (Cal Spas policy)
Returns	Non-returnable
Parts4Tubs Stock	7 in stock

⚠️ Electrical specifications (voltage, heater kW, pump configuration, service amperage, breaker size) vary by individual spa configuration. Always confirm from the system label inside your spa’s equipment enclosure before installation. Do not assume specifications based on appearance or model name.

🔗 Compatibility Guide

Compatible Spa Systems:

This board is designed for Cal Spas hot tubs equipped with the VS300 control system and displaying chip number CS5900R1(x) on the circuit board.

How to Identify Your Existing Board:

1. Open the spa equipment compartment
2. Locate the circuit board inside the control box
3. Find the white sticker on or near the board:
   • Chip number should show CS5900R1(x) — where x is any letter A through F
   • Balboa 5-digit number should show 55237
4. Match both numbers before ordering

Replaces / Cross-Reference Part Numbers:

Part Number	Description
ELE09100219	Cal Spas OEM PN (this board)
CALELE09100219	Cal Spas alternate catalog format
55237	Balboa circuit board PN
CS5900R1A	Chip revision A
CS5900R1B	Chip revision B
CS5900R1C	Chip revision C
CS5900R1D	Chip revision D
CS5900R1E	Chip revision E
CS5900R1F	Chip revision F

ℹ️ Note on 55236: Balboa system PN 55236 refers to the complete Cal Spas CS5900 spa pack (control box assembly), which is now obsolete and discontinued. The circuit board itself — sold here as ELE09100219 / 55237 — is a separate part and remains available.

Compatible Sensor:

Part Number	Description
53605	Balboa M7 Sensor Assembly — Temp/Hi-Limit

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🛠️ Installation Requirements

⚠️ Installation must be performed by a licensed electrician in compliance with NEC and all applicable local codes.

Pre-Installation Checklist:

• [ ] Confirm chip number on existing board is CS5900R1(x) (R1A through R1F)
• [ ] Confirm Balboa board number 55237 on sticker
• [ ] Note all DIP switch and jumper settings before removal
• [ ] Record your spa’s voltage and electrical configuration from the system label
• [ ] Disconnect all power at the GFCI breaker or disconnect
• [ ] Allow 5 minutes for capacitor discharge after power-off
• [ ] Photograph all wiring connections before removal

Electrical Requirements:

Requirement	Specification
Supply Voltage	Confirm from spa system label
GFCI Protection	Class A GFCI required — NEC Article 680
Ground & Bonding	Required — NEC Article 680
Dedicated Circuit	Required
Disconnect Box	Within line of sight, at least 5 ft from spa
Wire Type	Copper conductors only

⚠️ Do not assume voltage or breaker size. Confirm all electrical specifications from the system label inside your equipment enclosure before ordering or installing.

⚠️ Safety Warnings

• ⚠️ ALWAYS disconnect all power before circuit board work
• ⚠️ Licensed electrician installation required; NEC Article 680 compliance mandatory
• ⚠️ Class A GFCI required; grounding and bonding required per NEC Article 680
• ⚠️ Verify all electrical specs from your system label — do not assume
• ⚠️ Identify by chip number CS5900R1(x) and board number 55237 — not by spa model name
• ⚠️ 55236 is the spa pack PN, not the circuit board — ordering the wrong item will result in receiving the wrong part
• ⚠️ Non-returnable — confirm compatibility before ordering

❓ Frequently Asked Questions

Q: How do I confirm this is the right board for my Cal Spa? A: Look on your existing circuit board for the white sticker. The chip number should show CS5900R1(x) — where x is any letter A through F. The Balboa 5-digit number should show 55237. Both confirm this is the correct board. If you need help identifying your board, contact Parts4Tubs with your chip number and spa serial number.

Q: What is the difference between 55236 and 55237? A: 55236 is the Cal Spas CS5900 spa pack — the complete control box assembly including board, enclosure, and associated components. That spa pack is now obsolete and discontinued. 55237 is the circuit board PCB only — the individual board sold here, which is still available as a replacement part.

Q: What sensor does this board use? A: This board is compatible with the Balboa M7 Sensor Assembly, part number 53605. If your existing sensors are worn, order the 53605 separately when replacing the board.

Q: What warranty is included? A: Cal Spas circuit boards carry a 30-day limited warranty from the date of purchase. This is the Cal Spas OEM warranty, which is shorter than the standard 1-year Balboa warranty on non-OEM boards. Contact Parts4Tubs for full warranty terms.

Q: Is the complete CS5900 spa pack available? A: The Cal Spas CS5900 spa pack (55236) is discontinued. However, the circuit board itself (55237 / ELE09100219) is available here at Parts4Tubs. If you need a complete replacement control system, contact Parts4Tubs for current replacement options.

Q: What topside panel is compatible? A: This board uses an 8-wire phone-style topside connector. Compatible panels use the same connector format. Contact Parts4Tubs with your spa’s model and serial number for current topside panel recommendations.

✅ Why Choose the Cal Spas CS5900R1(x) (ELE09100219)

✅ Genuine Cal Spas OEM board — Balboa-manufactured, factory-programmed for VS300 systems
✅ Covers all CS5900R1 chip revisions — R1A through R1F
✅ M7® integrated dual-sensor technology — precision temperature and flow protection
✅ 7 in stock — ships promptly from Parts4Tubs
✅ Parts4Tubs verifies chip and compatibility before you order

🤝 Why Buy from Parts4Tubs

✅ Fast US shipping — 7 in stock, ships promptly
✅ Expert technical advice from Cal Spas and Balboa specialists
✅ Competitive pricing
✅ Balboa M7 Sensor Assembly (53605) and compatible topside panels available
✅ Chip and compatibility verification before ordering

🔌 Summary

The Cal Spas circuit board CS5900R1(x) (ELE09100219, Balboa PCB PN 55237) is a genuine OEM replacement PCB manufactured by Balboa Water Group for Cal Spas VS300 series systems. It uses M7® integrated dual-sensor technology and connects via an 8-wire phone-style topside connector. All chip revisions R1A through R1F are covered by this part number. Note that 55236 refers to the complete CS5900 spa pack (discontinued), not this individual circuit board. Electrical specifications including voltage, heater kW, and pump configuration must be confirmed from your spa’s system label before installation. This board carries a 30-day limited Cal Spas warranty and is non-returnable. Parts4Tubs has 7 in stock.

Finding and identifying a replacement Hot Tub Circuit Board (PCB)

If you are looking to replace a failed PCB on your Hot Tub’s spa pack, then quite often identifying the part that you need can be the hardest thing.

Firstly, you are looking for a model number on the actual circuit board itself. Having the model or serial of your hot tub is not going to help at this point, you need to find the number on the PCB itself.

Now, with certain brands of PCB, the number of the replacement PCB that you need is not going to match identically the one you are replacing. Why is that I hear you ask?

Well, normally, it is an updated version. This means that it might have updated firmware on the PCB or be a later revision. Normally, this means that the part number would be slightly different. This is usually indicated with a “12345678 -x” at the end of that part number where x indicated a firmware revision.

In some cases, there will be some following letters on the part number of the circuit board, “12345678 -x MAS” this can indicate that the PCB was used for an OEM meaning it was produced for a certain hot tub manufacturer and the letters identify the manufacturer.

This means if you source an original PCB, it will not have the letters, but will in most cases work just fine.

It can be confusing I know!

What if you can’t find a model number?

If you can’t find a model number on the PCB itself, then you need to look for a model number on the spa pack. Normally, there is a sticker on the outside of the spa pack that tells you the current ratings and input voltages etc and this will have a model number.

In general, most spa packs in the USA are manufactured by Balboa, Hydro-Quip, ACC or Gecko. I know I am generalising here, but if you have a spa pack that has the brand of your hot tub on, it will be an OEM so the key is identifying who made the original box.

From there, you can normally find an original PCB that you will be able to switch out.

For example, the Balboa VS (value series) is a very popular spa pack that has been used by multiple hot tub manufacturers under their own brand names. Whatever they have called it, strip it back and it is still a Balboa VS.

Visual Inspection

One of the most important things you can do when you are looking for a replacement is to visually inspect the PCB that you have versus the picture online of the replacement you are considering. They need to look the same even if there are the differences in firmware revisions or OEM part numbers, you should be visually replacing a PCB that looks like the one you have.

Configuring a replacement Hot Tub Circuit Board (PCB)

When you get a new PCB, you are more than likely going to need to configure it. Most PCBs have a number of different modes and setups that the can operate in. For this, you will need to manual or spec sheet to guide you.

For things like DIP switches, most of the time you can copy the settings from your original circuit board. You are looking for things like setting the voltage as a lot of PCBs can be configured to run on both 115V and 230V.

You may need to move jumpers or even wires to configure voltages – the key here is that you read the schematic and don’t expect the PCB to just work out of the box – it usually doesn’t.

Troubleshooting a Hot Tub Circuit Board (PCB)

Here are some common things you will see when you replace a PCB on a hot tub.

You press the buttons on the topside control and they don’t control the right parts (pumps or blower etc) – this is a mode configuration thing and you will either need to change some DIP switches on the PCB or an internal or low level programming mode on the topside control. Check the manual for how to do this.

You turn on the hot tub and it trips the breaker – it is not common for a new PCB to fail out of the box (I have not seen one yet!) However, a common mistake is that the voltage has not been set correctly. If it is set for 115V and then you try and turn it on, the current draw will be a lot more (twice) than expected and the breaker will trip.

To check this, unplug all of your kit – heater, pumps, blower and then turn on the PCB. If it trips with nothing plugged in, usually the voltage is incorrectly set and what is happening is that live current is being sent to the ground – because you have 4 wires into the PCB rather than 3. Current on the ground loop causes the trip. Check the settings to make sure it is configures for 230V.

It might not trip until you physically turn on a pump or a blower. As mentioned, if the pack is set to 115V and your pump is meant for 230V, it will draw twice the current at half the voltage and trip your breaker. Check the manual for info on how to set the voltage.